1. Technical Field
The present invention relates generally to an ad-hoc multimedia group communication terminal which is robust to packet loss and a method of operating the same, and, more particularly, to an ad-hoc multimedia group communication terminal which is adaptive to wireless channel variations and robust to packet loss and a method of operating the same provided as a plan which enables media data to be successfully transmitted in a wireless ad-hoc network environment in which a large amount of packet loss and variations in transmission delay are generated due to a channel fading phenomenon and channel noise.
2. Description of the Related Art
Recently, with the rapid developments in wireless network technology and at the requests of users for various types of media service, research into and the development of media transmission via a wireless network have been actively moving forward. In particular, media streaming should be able to transmit each packet within a predetermined delay time while overcoming variations in a network.
However, media streaming in a wireless network has the problems of packet transmission delay, packet loss, and variations in bandwidth attributable to the characteristics of channels and the performance of mobile terminals. Most of all, wireless channel fading phenomenon and channel noise cause a large amount of channel errors. In order to overcome such a problem, a transmission error control, such as Automatic Repeat reQuest (ARQ), is performed on a link layer in a typical wireless network.
However, all the errors cannot be overcome using the above-described methods, and the frequent movement of nodes and signal interference cause packet loss and variations in transmission delay, thereby generating a rapid deterioration in the picture quality of streaming media.
Therefore, in order to successfully transmit media in a wireless ad-hoc network environment where there are severe channel variations, a transmission technology and an error control technology which are fluid in an application layer level and adaptive to a network are required.
An error recovery method of retransmitting one or more lost packets in a wireless ad-hoc network environment, in which nodes frequently move and signal interference is frequently performed, is effective from the point of view of reliability. However, the error recovery method causes considerable delay which cannot be estimated and the error recovery method is not appropriate for multimedia application services which have strict real-time restrictions.